In a prior art, an apparatus for moving a laser convergent light beam radiating on a track of an optical disk in a direction traversing the track of the optical disk comprises first means to drive a reflector plate or an objective lens within an optical pick-up so as to be operated at a relatively high speed and corresponding to a small moving width and second means to drive the whole optical pick-up at a relatively low speed and corresponding to a large moving width. The first and second means are effectively operated so that the laser convergent light beam is moved in the direction traversing the track of the optical disk. Alternatively, the second means is only used so as to cover the whole movement of the laser convergent light beam. It will be noted that the whole pick-up should be moved in either case.
It will be understood that the optical pick-up is required to be moved in the direction traversing the track of the optical disk in case that the radiation point of the laser convergent light beam on the optical disk should be moved to a desired position. However, it will take substantial time for the optical pick-up to move due to its large inertia mass. Thus, writing signals on the optical disk and/or reading them from the optical disk will be difficult to be accomplished at high speed.